Power-hungry TVs will be banned from store shelves in California after state regulators Wednesday adopted a first-in-the-nation mandate to reduce electricity demand.

On a unanimous vote, the California Energy Commission required all new televisions up to 58 inches to be more energy efficient, beginning in 2011.

The requirement will be tougher in 2013, with only a quarter of all TVs currently on the market meeting that standard.

The commission estimates that TVs account for about 10 per cent of a home's electricity use.

The concern is that the energy draw will rise by as much as 8 per cent a year as consumers buy larger televisions, add more to their homes and watch them longer.

Commissioners say energy efficiency standards are the cheapest and easiest way to save electricity.

"We have every confidence this industry will be able to meet the rule and then some," Energy Commissioner Julia Levin said.

"It will save consumers money, it will help protect public health, and it will spark innovation."

TVs larger than 58 inches, which account for no more than 3 per cent of the market, would not be covered by the rule, a concession to independent retailers that sell high-end home-theatre TVs.

Environmental groups supported the tougher standards and hoped they will prompt manufacturers to make new energy-efficient models for the rest of the US.

They said the rules would cut California's power bill by US$1 billion a year, avoiding the need to build a 500-megawatt power plant.

Some manufacturers said implementing a power standard will cripple innovation, limit consumer choice and harm California retailers because consumers could simply buy TVs out of state or order them online.

Industry representatives also have said the standards would force manufacturers to make televisions that have poorer picture quality and fewer features than those sold elsewhere in the US.

As an example of the new standards, all new 42-inch television sets must use less than 183 watts by 2011 and less than 116 watts by 2013.

That's considerably more efficient than flat-screen TVs placed on the market in recent years.